Table 1.
Optimization of the pyridine directed direct arylation of 11 a.
| Entry | Solvent | T [°C] | Additives [equiv.] | Conversion[a,b] | |
|---|---|---|---|---|---|
| 1[c] | DCM | 135 | BQ (1.0) DMSO (4.0) | Ag2CO3 (2.0) H2O (8.0) | 50 |
| 2[c] | toluene | 120 | BQ (1.0) DMSO (4.0) | Ag2CO3 (2.0) H2O (8.0) | 61 |
| 3[d] | DCM | 135 | BQ (1.0) DMSO (4.0) | Ag2CO3 (2.0) H2O (8.0) | 60 |
| 4[d] | DCB | 140 | BQ (1.0) DMSO (4.0) | Ag2CO3 (2.0) H2O (8.0) | 42 (40) |
| 5[d] | DCE | 120 | BQ (1.0) DMSO (4.0) | Ag2CO3 (2.0) H2O (8.0) | 100 (62) |
| 6[d] | toluene | 120 | BQ (1.0) DMSO (4.0) | Ag2CO3 (2.0) H2O (8.0) | 100 (67) |
| 7[d] | toluene | 120 | BQ (1.0) | Ag2CO3 (2.0) | 78 (24) |
| 8[d] | toluene | 120 | Cu(OTf)2 (1.0) | Ag2O (1.0) | 44 |
| 9[d] | toluene | 120 | Cu(OTf)2 (1.0) | Ag2O (1.0) | 58 |
| 10[d] | toluene | 120 | BQ (0.5) | Ag2O (1.0) | 47 (10) |
| 11[d] | THF | 60 | BQ (0.5) | Ag2O (1.0) | 54 |
| 12[d] | THF | 60 | BQ (0.5) | Ag2O (1.0) | 82 |
| 13[d] | THF | 80 | BQ (0.5) | Ag2O (1.0) | 100 (69) |
| 14[d] | THF | 80 | Ag2O (1.0) | n.c.[e] | |
| 15[d] | THF | 80 | BQ (0.5) | 30 | |
| 16[d] | THF | 80 | BQ (1.0) | 59 |
[a] Determined by GC–MS with dodecane as the internal standard. [b] Isolated yield in parentheses. [c] 2.5 equiv. Ph—BF3K as aryl donor. [d] 3.0 equiv. Ph—B(OH)2 as aryl donor. [e] n.c.=No conversion.